rog-ers



(No Model.)

J. H. ROGERS. ELECTRIC TELEPHONE. No 252,521.

Patented J an. 17, 1882 Even t amesfiu-ris N, P511322 sssss \0-|.imagrnpppp Wllshi n nnnnnn c.

U1,;\TITED STATES PATENT OFFICE.

JAMES H. ROGERS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO FRANKHUME AND L. G. HINE, OF SAME PLACE.

ELECTRIC TELEPHONE.

SPECIFICATIONfOrming part of Letters Patent No. 252,521, dated January17, 1882,

Application filed November 9, 1881. (No model.)

To all whom itmag concern Be it known that 1, JAMES HARRIS ROGERS,acitizen of the United States, residing at Washington, in the Districtof Columbia, have invented newand useful Improvements in ElectricTelephones, of which the following is a specification.

My invention relates to that class of transmitters in which theelectrical waves or unduio lations traveling the circuit are produced byvariations of cross-section, quantity, or bulk of a fluid-conductor, andconsequently its conductivity, placed in the line, which variations arecaused by the vibrations of the transmtr5 ting diaphragm.

The object of my invention is to improve the construction of suchinstruments and to render them more delicate and practical.

The accompanying drawing is a vertical section through my improvedinstrument.

The caseAof the transmitteris supported in a substantially horizontalposition in any suitable place and manner, and is provided with amouthpiece or vocalizing-chamber, B, which is curved toward the speaker,so that the edge ofits mouth isin a substantially vertical plane. Thediaphragm G is secured in the frame or case, as usual, andcarries uponits center a downwardly-projecting tube, D, of non-con- 0 ductingmaterial. Just below the diaphragm acu p, E, ot'non-conducting material,is secured. This cup has two binding-screws, F and G, one, F, of whichis connected centrally with the cup, so as to establish connection withthe 5 fluid-conductor H within it, and the other screw, G, is similarlysecured in any suitable position, preferably in the side ofthe cup. Thewire I from the battery M B passes from the binding-screw t in the caseof the instrument to the central screw, F, in the cup, while theline-wire K extends from the screw. G to the binding-Screw 7c. Thedownwardly-projecting tube D extends into the fluid-conductor over thebinding-screw F and in close proximity to 5 the bottom of the cup.Fluid-conductors Hot any suitable character may be used. There are manythat will answer the purpose for instance, dilute of sulphuric acid,mercury, sal-ammoniac, 8w. t

It will be obvious that the variations of the diaphragm caused by soundsuttered in its vicinity will cause the non conducting tube D to approachcloser to and recede from. the bottom of the cup containing the fluid,and that these variations of distance will cause corresponding changeslu'the cross-sections, volume, or quantity of the fluid at the point X,between the end of the tube and the bottom of the cup. Thus theresistance of the fluid in the circuit is increased or decreased incorrespondence to the vibrations of the transmitting-diaphragm, andwaves or undulations corresponding to the sound-waves produced by thesound uttered at the diaphragm arecaused in the electric circuit, sothat the sound uttered at the transmitter will be accurately reproducedat the receiving-station, as will be well understood.

Receivers of any well-known form may be used in circuit with myinstrument.

The apparatus above described is Vt ry sen- 7o sitive and produceselectrical im pulses of large amplituideintheline.Suitableopeningsshould be left in the cup to permit the gases generatedby the electrolytic action to escape.

Having thus describedmy invention, what I claim isy 1. The combinationof the diaphragm, the downwardly-projecting non-conducting tube, thecup, the fluid-conductor, and its bindingscrews.

- 8o 2. The combination of a battery, the linewires, a diaphragm, afluid-conductor forming part of the circuit, the non-conductingcontaining-cup, and a non-conducting tube projecting from the diaphragm,which projects 8 into the fluid and serves to increase and decrease itscross-section at a given point between'the end of the projection and thecup, substantially as set forth.

'In testimony whercotl have hereunto set my hand in the presence of twosubscribing witnesses.

JAS. HARRlS ROGERS.

Witnesses: I I

JAMES L. NORRIS, I. W. ROGERS.

